A blood vessel or other bodily passage may be used to access parts of the body to deliver an agent to a target site in the wall of the vessels. For example, the renal arteries may be used as access pathways to deliver a therapeutic agent to the renal nerves, which run within the wall of the renal arteries. However, it may be difficult to deliver therapeutic agents with sufficient precision to the renal nerves. One approach is to “flood” the entire region about the circumference of the renal artery using the agent. This approach uses more of the agent than is necessary and may be toxic to the patient or surrounding tissues. Moreover, the toxicity concerns can also significantly limit the selection of particular therapeutic agents to kill nerves and the ability to provide effective treatment.
What is needed is a way of locally delivering the amount of an agent needed to effect a desired therapeutic response while reducing injury or harm to surrounding tissue. What is also needed is a way of delivering an agent to a target site within the wall of a blood vessel with increased precision and a way of removing or neutralizing excess amount of agents to reduce potential toxicity effects or vascular trauma.
Nerve denervation may be used to manage hypertension, congestive heart failure, endstage renal disease, and other conditions. Radio frequency (RF) ablation of the renal nerves has been practiced and often lacks fine control, and may cause unintended damage to neighboring tissue such as the endothelium lining blood vessels and smooth muscles that constitute blood vessel walls, resulting in vessel injury or occlusion.
What is needed are methods, devices, and agents for renal denervation which offer greater control over the denervation process than RF ablation or bolus injection, and the appropriate chemistry for controlled delivery and subsequent neutralization to reduce vessel occlusion, spasm, or other tissue damage.